C# MD5 哈希器示例

发布于 2024-07-18 04:51:52 字数 779 浏览 6 评论 0原文

编辑：我已将其重新命名为示例，因为代码按预期工作。

我正在尝试复制文件，获取 MD5 哈希值，然后删除副本。我这样做是为了避免另一个应用程序写入的原始文件上的进程锁定。但是，我复制的文件被锁定。

File.Copy(pathSrc, pathDest, true);

String md5Result;
StringBuilder sb = new StringBuilder();
MD5 md5Hasher = MD5.Create();

using (FileStream fs = File.OpenRead(pathDest))
{
    foreach(Byte b in md5Hasher.ComputeHash(fs))
        sb.Append(b.ToString("x2").ToLower());
}

md5Result = sb.ToString();

File.Delete(pathDest);

然后我在 File.Delete() 上收到“进程无法访问文件”异常。

我希望使用 using 语句可以很好地关闭文件流。我还尝试单独声明文件流，删除 using，并将 fs.Close() 和 fs.Dispose() 放在读取之后。

之后，我注释掉了实际的 md5 计算，并且代码执行，文件被删除，所以看起来它与 ComputeHash(fs) 有关。

原文

Edit: I've retitled this to an example as the code works as expected.

I am trying to copy a file, get a MD5 hash, then delete the copy. I am doing this to avoid process locks on the original file, which another app writes to. However, I am getting a lock on the file I've copied.

File.Copy(pathSrc, pathDest, true);

String md5Result;
StringBuilder sb = new StringBuilder();
MD5 md5Hasher = MD5.Create();

using (FileStream fs = File.OpenRead(pathDest))
{
    foreach(Byte b in md5Hasher.ComputeHash(fs))
        sb.Append(b.ToString("x2").ToLower());
}

md5Result = sb.ToString();

File.Delete(pathDest);

I am then getting a 'process cannot access the file' exception on File.Delete()'.

I would expect that with the using statement, the filestream would be closed nicely. I have also tried declaring the filestream separately, removing using, and putting fs.Close() and fs.Dispose() after the read.

After this, I commented out the actually md5 computation, and the code excutes, with the file being deleted, so it looks like it's something to do with ComputeHash(fs).

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柒夜笙歌凉 2024-07-25 04:51:52

导入名称空间

using System.Security.Cryptography;

这是返回 md5 哈希码的函数。您需要将字符串作为参数传递。

public static string GetMd5Hash(string input)
{
        MD5 md5Hash = MD5.Create();
        // Convert the input string to a byte array and compute the hash.
        byte[] data = md5Hash.ComputeHash(Encoding.UTF8.GetBytes(input));

        // Create a new Stringbuilder to collect the bytes
        // and create a string.
        StringBuilder sBuilder = new StringBuilder();

        // Loop through each byte of the hashed data 
        // and format each one as a hexadecimal string.
        for (int i = 0; i < data.Length; i++)
        {
            sBuilder.Append(data[i].ToString("x2"));
        }

        // Return the hexadecimal string.
        return sBuilder.ToString();
}

Import the name space

using System.Security.Cryptography;

Here is the function that returns you md5 hash code. You need to pass the string as parameter.

public static string GetMd5Hash(string input)
{
        MD5 md5Hash = MD5.Create();
        // Convert the input string to a byte array and compute the hash.
        byte[] data = md5Hash.ComputeHash(Encoding.UTF8.GetBytes(input));

        // Create a new Stringbuilder to collect the bytes
        // and create a string.
        StringBuilder sBuilder = new StringBuilder();

        // Loop through each byte of the hashed data 
        // and format each one as a hexadecimal string.
        for (int i = 0; i < data.Length; i++)
        {
            sBuilder.Append(data[i].ToString("x2"));
        }

        // Return the hexadecimal string.
        return sBuilder.ToString();
}

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淡莣 2024-07-25 04:51:52

我把你的代码放在控制台应用程序中并运行它，没有错误，得到了哈希值，并且测试文件在执行结束时被删除？我刚刚使用测试应用程序中的 .pdb 作为文件。

您运行的 .NET 版本是什么？

我将可用的代码放在这里，如果您将其放入 VS2008 .NET 3.5 sp1 中的控制台应用程序中，它运行时不会出现错误（至少对我来说）。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Security.Cryptography;
using System.IO;

namespace lockTest
{
    class Program
    {
        static void Main(string[] args)
        {
            string hash = GetHash("lockTest.pdb");

            Console.WriteLine("Hash: {0}", hash);

            Console.ReadKey();
        }

        public static string GetHash(string pathSrc)
        {
            string pathDest = "copy_" + pathSrc;

            File.Copy(pathSrc, pathDest, true);

            String md5Result;
            StringBuilder sb = new StringBuilder();
            MD5 md5Hasher = MD5.Create();

            using (FileStream fs = File.OpenRead(pathDest))
            {
                foreach (Byte b in md5Hasher.ComputeHash(fs))
                    sb.Append(b.ToString("x2").ToLower());
            }

            md5Result = sb.ToString();

            File.Delete(pathDest);

            return md5Result;
        }
    }
}

I took your code put it in a console app and ran it with no errors, got the hash and the test file is deleted at the end of execution? I just used the .pdb from my test app as the file.

What version of .NET are you running?

I am putting the code that I have that works here, and if you put this in a console app in VS2008 .NET 3.5 sp1 it runs with no errors (at least for me).

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Security.Cryptography;
using System.IO;

namespace lockTest
{
    class Program
    {
        static void Main(string[] args)
        {
            string hash = GetHash("lockTest.pdb");

            Console.WriteLine("Hash: {0}", hash);

            Console.ReadKey();
        }

        public static string GetHash(string pathSrc)
        {
            string pathDest = "copy_" + pathSrc;

            File.Copy(pathSrc, pathDest, true);

            String md5Result;
            StringBuilder sb = new StringBuilder();
            MD5 md5Hasher = MD5.Create();

            using (FileStream fs = File.OpenRead(pathDest))
            {
                foreach (Byte b in md5Hasher.ComputeHash(fs))
                    sb.Append(b.ToString("x2").ToLower());
            }

            md5Result = sb.ToString();

            File.Delete(pathDest);

            return md5Result;
        }
    }
}

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